[FIX] hr_timesheet: handle case when has never signed in

The search may return zero results if an employee has never signed in. In this case the browse would have failed.

addons/hr_attendance/hr_attendance.py

@@ -61,6 +61,7 @@ class hr_attendance(osv.osv):
                     ('employee_id', '=', obj.employee_id.id),
                     ('name', '<', obj.name), ('action', '=', 'sign_in')
                 ], limit=1, order='name DESC')
+                if last_signin:
                     last_signin = self.browse(cr, uid, last_signin_id, context=context)[0]
 
                     # Compute time elapsed between sign-in and sign-out
@@ -68,6 +69,8 @@ class hr_attendance(osv.osv):
                     signout_datetime = datetime.strptime(obj.name, '%Y-%m-%d %H:%M:%S')
                     workedhours_datetime = (signout_datetime - last_signin_datetime)
                     res[obj.id] = ((workedhours_datetime.seconds) / 60) / 60
+                else:
+                    res[obj.id] = False
         return res
 
     _columns = {